The present invention relates generally to automated processing of semiconductor wafers and more specifically to the use of split runcards for selecting alternate processing steps in such automated semiconductor processing.
Modem semiconductor fabrication facilities (often referred to as FABs) typically use MES (manufacturing execution system) to control xe2x80x9cLotxe2x80x9d flow equipment operations and proper conditions to achieve fully automated operations. One successful MES solution is the SiView standard system produced by IBM which supports the integration of an AMHS (Automated Material Handling System) and supports use of 300 mm FOUPs (Front Opening Unified Pods) while also maintaining support of a 200 mm carrier system.
A unified pod for processing wafers carefully maintains the purity of a small inside space of the unified pod. Because the purity of the small inside space of the pod is controlled, the purity of the clean room is less critical. Thus, the use of a unified pod saves wafer manufacturing equipment cleaning costs. However, external dust or human body dust may be carried into the manufacturing equipment when opening the cover of the typical unified pod, and thereby contaminate the wafers. A FOUP (Front Open Unified Pod) auto loading structure is suitable for use in the loading-in-interface in a wafer manufacturing process to automatically close/open the cover of a FOUP and thereby help avoid this type of contamination. The FOUP includes a machine base, a carriage, a sliding control mechanism, a clamping mechanism, a horizontal shifting mechanism and a lifting mechanism. The FOUP is put on the carriage and held down by the clamping mechanism. It is then moved in contact with a gate on an axis on a backboard of the machine base. A cover of the FOUP is then opened by a cover close/open control mechanism at the back of the gate. The cover is then carried backward away from the FOUP by the horizontal shifting mechanism and then lowered with the lifting mechanism. The cover is closed on the FOUP when reversing the procedure. The automatic FOUP cover closing/opening operation helps prevent wafer contamination.
The SiView standard system conforms to industry standards and allows for a high degree of changes and inter-operability, RandD experiments, STR (special test report) requests, tuning of equipment recipes, etc. Changes in the type, order or parameters of the automated processes for such experiments and STR requests are typically initiated by a xe2x80x9clist of new processes,xe2x80x9d changes in the order of processing, or process parameters which are changed to or in addition to an existing or defined automatic process. This list is often referred to as a xe2x80x9cRuncard,xe2x80x9d or more specifically as a xe2x80x9cSplitxe2x80x9d Runcard. However, such changes as specified by a xe2x80x9cSplitxe2x80x9d Runcard cannot be automatically handled or tracked by the system. Consequently, until the present invention it was necessary that FAB operators manually assign the equipment ID required by a recipe and use a manual mode to process a xe2x80x9cLotxe2x80x9d of wafers according to a Split Runcard that deviated from the pre-defined semiconductor processes carried out automatically by an IBM SiView standard system.
These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present invention as discussed below.
A method for changing various recipes, order of processing steps and processing parameters used in processing wafers while continuing to maintain an automated process is provided according to this invention. The method comprises providing a multiplicity of wafer processes available for use in the manufacture of semiconductor devices. A first sequence of standard actions or steps is defined for processing a particular xe2x80x9cLotxe2x80x9d or group of wafers. The sequence of standard actions or steps comprise selected ones of the multiplicity of wafer processes including at least one specific identified process of the multiplicity. This standard or first sequence of actions is typically defined by a xe2x80x9cRuncard.xe2x80x9d A second sequence of actions is defined by means of a xe2x80x9cSplitxe2x80x9d Runcard. The second sequence of actions also comprises at least one of the multiplicity of the wafer processes as mentioned above. The processing of the wafers is then started at an xe2x80x9cinitial actionxe2x80x9d so as to begin the processing of a xe2x80x9cLotxe2x80x9d of wafers according to the first sequence of actions. The xe2x80x9cLotxe2x80x9d of wafers is adapted for being subdivided into a first group and a second group, and will then move through the various standard processing steps according to the first sequence of actions as defined by the xe2x80x9cRuncardxe2x80x9d until the processing is interrupted just prior to being subjected to a particular identified process defined by the xe2x80x9cRuncard.xe2x80x9d After being interrupted, the Lot of wafers is separated into a first group and a second group. Processing of the first group of wafers then continues according to the second sequence of actions or the xe2x80x9cSplit Runcard,xe2x80x9d after which the first group and second group are rejoined or merged and the processing of the combined first and second groups continues according to the first sequence of actions or standard xe2x80x9cRuncard.xe2x80x9d
According to one embodiment, after the interrupting step and processing of the first group of wafers according to the second sequence of actions or Split Runcard is complete, the second group of the Lot is further processed according to the particular identified process before the first and second groups of wafers are merged.
According to a another embodiment, processing of the second group occurs subsequent to the first group being processed by at least two of the multiplicity of wafer processes and before the merger of the two groups.
According to still another embodiment, the second group of wafers is subjected to at least two processes after the interruption step and before the merging step. Thus, according to this embodiment, at least two processes in the first sequence of steps are replaced by the second sequence of actions or steps used to process the first group of wafers.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent processes or methods do not depart from the spirit and scope of the invention as set forth in the appended claims.